The invention relates to novel catalyst systems characterized in that aluminium alkyl complexes of the formula (I), such as described in DE 19753135 applied to magnesium chloride, SiO2 or SiO2 in combination with MgCl2 as support in the presence of titanium halides or vanadium halides act both as cocatalysts and as stereo-selectivity promoters in heterogeneous polymerizations of xcex1-olefins, 
where
X1 is NH, NH2*, NHxe2x80x94A*, NHxe2x80x94SiA3*, Nxe2x80x94A, NSiA3, N(A)2*, N(SiA3)2*, O, OSiA2, OA*, OSiA3*, OAryl*, S, SSiA2, SA*, SSiA3*, PA, PSiA3, P(A)2*, P(SiA3)2* or a single bond,
X2 is NH, Nxe2x80x94A, NSiA3, O, OSiA2, S, SSiA2, PA or X1 coordinated to Al(R1)3, or a single bond,
R1 is H; Hal when n=0; A, if desired covalently bound to Al; Si(A)3 when X1=O,
R2 is A, if desired covalently bound to Al;
xe2x80x83CH2xe2x80x94CHxe2x95x90CH, CH2xe2x80x94Cxe2x89xa1C when Z1=H; 
R3 and R4 are each, independently of one another, a bond or R2 or Si(A)3 or Si(A)2,
Z1 is a bond or H bound to R2,
Z2 is a bond or H bound to R2 and R3, where
A is branched or unbranched C1-C7-alkyl, -alkylidene or -alkenylidene,
Aryl is phenyl, naphthyl, indenyl, fluorenyl,
Hal is F, Cl,
and, independently of one another,
n is 0 or 1,
m is 0 or 1,
p is 0 or 1,
q is 1 or 2,
l is 0 or 1,
where coordinate bonds can exist between X1, X2 and Al, and R1, R2, R3, R4, X1, X2, Z1 and Z2 can, in each case independently of one another at different positions in the molecule, assume all meanings and X1 can assume only the meanings denoted by xe2x80x9c*xe2x80x9d when 1=0 and R1, R2, R3 or R4 are not present.
Ziegler-Natta-catalysed polymerization is a polymerization method which has been improved over a number of generations since the initial work by Ziegler and Natta in the 1950s. Seeking to increase both the activity and the stereoselectivity has been the driving force for the continuous development of the catalyst system. The system established at the present time is based on the use of a multicomponent catalyst. In addition to the support material, this comprises as actual catalyst a transition metal compound, e.g. a titanium compound, which is activated only by addition of an aluminium-containing cocatalyst. In addition, further constituents such as internal and external donors are necessary. The use of an internal donor prevents agglomeration of the catalytically active species, while the external donor improves the stereospecificity when using prochiral olefins. Thus, in a polymerization using liquid propene, the system MgCl2/ester/TiCl4/AlEt3/PhSi(OEt)3 makes it possible to achieve a productivity of 600 [kgpp/gTi] combined with an isotacticity of 98%. These catalyst systems save the costly removal of catalyst residues and the complicated extraction of atactic material from the polyolefins produced. The understanding which has now been gained regarding the relationship between catalyst and polymer morphology makes it possible to control the polymer morphology during the polymerization process, which eliminates additional processing steps such as extrusion and granulation. These advances have for the first time made it possible to carry out solvent-free gas-phase polymerization and bulk polymerization and have led to substantial simplifications in the case of suspension polymerization. [P. Galli, J. C. Haylock, Makromol. Chem., Macromol. Symp. 1992, 63, 19-54; P. Corradini, V. Buscio, G. Guerra, in Comprehensive Polymer Science, Vol. 4, G. Allen (Ed.), Pergamon Press, 1999, p. 29; C. Jenny, P. Maddox, Solid State and Mat. Science 1988, 3, 94; K. Soga, T. Shiono, Progress in Polymer Science 1997, 22, 1503].
DE 19753135 describes a series of aluminium compounds which have an intramolecular donor side chain, e.g. an amino-, thio- or oxo-coordinated side chain, and can be prepared by methods known to those skilled in the art for preparing organometallic compounds. These aluminium compounds act as cocatalytically activating components in Ziegler-Natta catalysts for the polymerization of ethylene. However, the polymerization of propylene or higher xcex1-olefins cannot be carried out successfully using the catalyst systems described in this patent application. Furthermore, the catalyst systems used there did not include a catalyst support, which makes them difficult or impossible to use in industrial plants and additionally does not allow the desired polymer morphology to be set.
Apart from the continual striving for more active and more selective catalyst systems, the following aspects are in need of improvement:
a) The catalyst systems used in industry comprise highly pyrophoric, reactive, volatile aluminium alkyl compounds as cocatalysts, in particular triethylaluminium. These compounds are highly sensitive to impurities in the reaction medium, for example to residual moisture in the monomers to be polymerized. In addition, the safe handling of such highly pyrophoric and volatile compounds requires expensive safety containers for storage and transport under absolute exclusion of oxygen and moisture. Furthermore, the industrial plants for catalyst preparation and polymerization have to be able to cope with these problems. This is, in particular, a problem for industrially relatively undeveloped countries and regions in which high temperatures and high atmospheric humidity prevail as a result of the climate.
b) To be able to achieve further increases in the yield of polymers in olefin polymerization, catalyst systems having higher activities have to be tailored and developed. The activity increase should be able to be achieved by optimization of the cocatalyst, since it converts the catalyst into the actual catalytically active species.
c) To achieve high stereoselectivities in the Ziegler-Natta catalysis of prochiral olefins, additional costly external donors such as PhSi(OEt)3 have to be used. The properties (tacticity and molecular weight distribution) of the polymers obtained using external donors have hitherto not been able to be optimized fully satisfactorily, so that there is a continuing need for polymers having improved properties.
d) Since the cocatalyst in Ziegler-Natta catalysts is usually used in a large excess relative to the catalyst and is thus the most costly component, there is great interest in reducing the cocatalyst/catalyst ratio while retaining the activities.
It is therefore an object of the present invention to provide catalyst systems which do not have the disadvantages listed under a), b), c) and d) and can be used both for the polymerization of ethylene and of propylene and higher xcex1-olefins. Another object of the present invention is to provide corresponding catalyst systems which are bound to suitable supports, simply and inexpensively. The catalyst systems of the present invention should be usable in industrial plants under simple conditions with a relatively small cocatalyst/catalyst ratio and should at the same time have activities which are better than those of previously known systems. Another object of the present invention is to provide corresponding catalyst systems which are less sensitive to impurities, in particular moisture.
Upon further study of the specification and appended claims, further objects and advantages of this invention will become apparent to those skilled in the art.
The invention includes catalyst systems comprising
a) aluminium alkyl complexes of the formula (I) 
xe2x80x83where
X1 is NH, NH2*, NHxe2x80x94A*, NHxe2x80x94SiA3*, Nxe2x80x94A, NSiA3, N(A)2*, N(SiA3)2*, O, OSiA2, OA*, OSiA3*, OAryl*, S, SSiA2, SA*, SSiA3*, PA, PSiA3, P(A)2*, P(SiA3)2* or a single bond,
X2 is NH, Nxe2x80x94A, NSiA3, O, OSiA2, S, SSiA2, PA or X1 coordinated to Al(R1)3, or a single bond,
R1 is H; Hal when n=0; A, if desired covalently bound to Al; Si(A)3 when X1=O,
R2 is A, if desired covalently bound to Al;
xe2x80x83CH2xe2x80x94CHxe2x95x90CH, CH2xe2x80x94Cxe2x89xa1C when Z1=H; 
R3 and R4 are each, independently of one another, a bond or R2 or Si (A)3 or Si(A)2,
Z1 is a bond or H bound to R2,
Z2 is a bond or H bound to R2 and R3, where
A is branched or unbranched C1-C7-alkyl, -alkylidene or -alkenylidene,
Aryl is phenyl, naphthyl, indenyl, fluorenyl,
Hal is F, Cl,
and, independently of one another,
n is 0 or 1,
m is 0 or 1,
p is 0 or 1,
q is 1 or 2,
l is 0 or 1,
where coordinate bonds can exist between X1, x2 and Al, and R1, R2, R3, R4, X1, X2, Z1 and Z2 can, in each case independently of one another at different positions in the molecule, assume all meanings and X1 can assume only the meanings denoted by xe2x80x9c*xe2x80x9d when l=0 and R1, R2, R3 or R4 are not present,
b) magnesium chloride, SiO2 or SiO2 in combination with MgCl2 as support material,
c) a catalyst selected from the group consisting of titanium halides and vanadium halides and
d) internal donors such as mono esters or diesters, e.g. ethyl benzoate, dimethyl phthalate, or internal donors with which those skilled in the art are familiar and, if desired, also external donors selected from the group consisting of compounds RSi(OR)3, e.g. PhSi(OEt)3, or external donors with which those skilled in the art are familiar.
In particular embodiments the invention is achieved by corresponding catalyst systems comprising at least one aluminium alkyl complex of the formula (I) selected from the group consisting of
[3-(dimethylamino)propyl]dimethylaluminium,
[3-(dimethylamino)propyl]methylaluminium chloride,
[3-(diethylamino)propyl]diethylaluminium,
[3-(diethylamino)propyl]dipropylaluminium,
[3-(diethylamino)propyl]dibutylaluminium,
[4-(diethylamino)butyl]dibutylaluminium,
[3-(dimethylamino)propyl]aluminium dichloride,
[2-(dimethylamino)benzyl]diethylaluminium,
[3-(dimethylamino)benzyl]ethylaluminium chloride,
[2,6-bis(dimethylaminomethyl)phenyl]diethylaluminium,
[8-(dimethylamino)naphthyl]dimethylaluminium,
[8-(dimethylamino)naphthyl]diethylaluminium,
1-[3-(dimethylamino)propyl]-1-aluminacyclohexane,
1-[3-(dimethylamino)-2-methylpropyl]-1-aluminacyclohexane,
1-[3-(dimethylamino)propyl]-1-aluminacycloheptane,
bis[3-(dimethylamino)propyl]methylaluminium,
1,5-dimethyl-1-alumina-5-azacyclooctane,
1-ethyl-5-methyl-1-alumina-5-azacyclooctane,
1-alumina-5-azabicyclo[3.3.3]undecane,
[4-(methoxy)butyl]dimethylaluminium,
[3-(ethoxy)propyl]diethylaluminium,
[3-(ethoxy)propyl]dibutylaluminium,
[3-(propoxy)propyl]dibutylaluminium,
[4-(ethoxy)butyl]dibutylaluminium,
[5-(ethoxy)pentyl]dibutylaluminium,
[3-(ethylthiopropyl)diethylaluminium,
[3-(ethylthiopropyl)dibutylaluminium,
bis{[2-(dimethylamino)ethoxy]dimethylaluminium}
bis{[2-(dimethylamino)ethoxy]diethylaluminium}
bis{[2-(diethylamino)ethoxy]diethylaluminium}
bis{[3-(diethylamino)propoxy]diethylaluminium}
bis{[2-(dimethylamino)ethoxy]dibutylaluminium}
bis{[2-(methoxy)ethoxy]dimethylaluminium}
bis{[3-(methoxy)propoxy]dimethylaluminium}
bis{[2-(methoxy)ethoxy]diethylaluminium}
bis{[2-(methoxy)ethoxy]dibutylaluminium}
bis{[2-(butoxy)ethoxy]dimethylaluminium}
bis{[2-(butoxy)ethoxy]dibutylaluminium}
bis{[2-(ethoxy)ethoxy]diethylaluminium}
bis{[2-(phenoxy)ethoxy]dimethylaluminium}
bis{[2-(methoxy)phenoxy]dimethylaluminium}
[2-(diethylamino)ethoxy]diethylaluminium.AlEt3 adduct,
[3-(diethylamino)propoxy]diethylaluminium.AlEt3 adduct,
[2-(methoxy)ethoxy]dimethylaluminium.AlMe3 adduct,
[2-(methoxy)ethoxy]diethylaluminium.AlEt3 adduct,
[2-(ethoxy)ethoxy]diethylaluminium.AlEt3 adduct,
[3-(ethoxy)propoxy]diethylaluminium.AlEt3 adduct,
[2-(methylthio)ethoxy]dimethylaluminium.AlMe3 adduct.
The present invention therefore also provides for the use of such a catalyst system in heterogeneous polymerizations of xcex1-olefins and prochiral olefins, in particular of ethylene and propylene.
In these reactions, the catalyst system of the invention can be used as a stereoselectivity promoter. The polymer properties can be controlled by selectively choosing the catalyst.
The present invention further provides a process for preparing catalyst systems according to the invention for the polymerization of xcex1-olefins or prochiral olefins. Depending on the application, the preparation can be carried out by
(a) applying a titanium or vanadium halide to MgCl2 or SiO2 or to a combination of SiO2 and MgCl2 as support and adding an internal donor such as monoesters or diesters, e.g. ethyl benzoate, dimethyl phthalate, or internal donors with which those skilled in the art are familiar and, if desired, also external donors selected from the group consisting of compounds RSi(OR)3, e.g. PhSi(OEt)3 or external donors with which those skilled in the art are familiar and an aluminium compound of the formula (I). or by
(b) applying an aluminium compound of the formula (I) to MgCl2, SiO2 or SiO2 in combination with MgCl2 as support and adding a titanium or vanadium halide and adding an internal donor such as monoesters or diesters, e.g. ethyl benzoate, dimethyl phthalate, or internal donors with which those skilled in the art are familiar and, if desired, also external donors selected from the group consisting of compounds RSi(OR)3, e.g. PhSi(OEt)3, or external donors with which those skilled in the art are familiar, or by
(c) applying an active species generated from an aluminium compound of the formula (I) and a titanium or vanadium halide to MgCl2 or SiO2 or to a combination of SiO2 and MgCl2 as support and adding an internal donor such as monoesters or, diesters, e.g. ethyl benzoate, dimethyl phthalate, or internal donors with which those skilled in the art are familiar and, if desired, also external donors selected from the group consisting of compounds RSi(OR)3, e.g. PhSi(OEt)3, or external donors with which those skilled in the art are familiar.
It has surprisingly been found that application of the aluminium compounds of the formula (I) to magnesium chloride or SiO2 or to a combination of SiO2 and MgCl2 as support in the presence of titanium or vanadium halides and internal donors such as monoesters or diesters, e.g. ethyl benzoate, dimethyl phthalate, or internal donors with which those skilled in the art are familiar and, if desired, also external donors selected from the group consisting of compounds RSi(OR)3, e.g. PhSi(OEt)3, or external donors with which those skilled in the art are familiar gives a catalyst system which, firstly makes possible the polymerization of xcex1-olefins, in particular propylene, in high yields and, secondly, leads to a tremendous increase in activity in the polymerization of ethylene even at 30xc2x0 C. compared with the unsupported catalyst systems. Various methods of application to the support have been developed:
(a) application of a titanium or vanadium halide to MgCl2 or SiO2 or to a combination of SiO2 and MgCl2 as support and addition of an internal donor such as monoesters or diesters, e.g. ethyl benzoate, dimethyl phthalate, or internal donors with which those skilled in the art are familiar and, if desired, also external donors selected from the group consisting of compounds RSi(OR)3, e.g. PhSi(OEt)3 or external donors with which those skilled in the art are familiar and addition of an aluminium compound of the formula (I)
(b) addition of an aluminium compound of the formula (I) to MgCl2 or SiO2 or to a combination of SiO2 and MgCl2 as support and addition of a titanium or vanadium halide and addition of an internal donor such as monoesters or diesters, e.g. ethyl benzoate, dimethyl phthalate, or internal donors with which those skilled in the art are familiar and, if desired, also external donors selected from the group consisting of compounds RSi(OR)3, e.g. PhSi(OEt)3, or external donors with which those skilled in the art are familiar,
(c) addition of an active species previously generated from the two components to MgCl2 or SiO2 or to a combination of SiO2 and MgCl2 as support and adding an internal donor such as monoesters or diesters, e.g. ethyl benzoate, dimethyl phthalate, or internal donors with which those skilled in the art are familiar and, if desired, also external donors selected from the group consisting of compounds RSi(OR)3, e.g. PhSi(OEt)3, or external donors with which those skilled in the art are familiar.
The experiments carried out indicated that the method (A) gives the highest activities during olefin polymerization. The use of selected donor-stabilized organoaluminium compounds also gives higher activities than those achieved in the prior art.
It has been found that the polymer properties can be controlled by choice of the cocatalyst.
The catalyst systems of the invention can advantageously be used under conditions which assist the process. The latter is particularly the case when using a cocatalyst/catalyst ratio lower than that hitherto customary. In particular, the polymerization properties can be controlled according to the invention by altering this ratio.
A further advantageous property which has been found is that the novel catalyst systems are quite stable to air, moisture and impurities in the reaction system and thus require technically less demanding containers for storage and transport or technically less complicated plants for the preparation of the catalyst and for the polymerization of olefins. The novel catalyst systems also have a high thermal stability and long life under reaction conditions.
Furthermore, it has surprisingly been found that the novel catalyst systems consisting of MgCl2 or SiO2 or a combination of SiO2 and MgCl2, a titanium or vanadium halide compound, an internal donor and an aluminium compound of the formula (I) are also stereoselective in the polymerization of prochiral olefins without addition of external donors.
The aluminium compounds of the formula (I) can therefore simultaneously perform a plurality of functions in the novel catalyst systems: they act firstly as cocatalysts and secondly as stereo-selectivity promoters. This makes it possible to reduce the number of catalyst components necessary by one component. The third function is to control the molecular structure of the polymers, e.g. molecular weights, molecular weight distributions, tacticities and branching, and thus the polymer properties such as hardness, stiffness, toughness, weldability, transparency, gas permeability and processability.
A reduction in the number of catalyst components also, in addition to the higher thermal stability and lower oxygen and moisture sensitivity found, makes the processes for catalyst preparation and olefin polymerization generally easier.
The low oxygen and moisture sensitivity of the aluminium compounds of the formula (I), which makes more convenient and safe handling possible, is achieved by means of the intramolecularly stabilizing donor group with coordinative saturation of the aluminium centre.
As described, the novel catalyst systems consist of support, catalyst, donor and cocatalyst:
Cocatalysts employed are the aluminium compounds of the formula (I).
Catalysts employed are compounds of transition metals of transition groups IV to VIII of the Periodic Table of the Elements, in particular compounds of transition metals of transition groups IV and V of the Periodic Table, in particular titanium and vanadium halide compounds. Examples of suitable compounds are TiCl4 and VCl4.
As catalyst support, it is possible to use anhydrous MgCl2 or SiO2 or a combination of SiO2 and MgCl2.
Donors used are internal donors such as monoesters or diesters, e.g. ethyl benzoate, dimethyl phthalate, or internal donors with which those skilled in the art are familiar and, if desired, also external donors selected from the group consisting of compounds RSi(OR)3, e.g. PhSi(OEt)3, or external donors with which those skilled in the art are familiar.
The preparation of the novel supported catalyst systems is carried out by a process which is disclosed with the aid of examples given in the following text. These examples are specific embodiments; a person skilled in the art will, on the basis of his technical knowledge, be able to replace means indicated therein by corresponding means having an equivalent action.
To prepare the supported catalyst systems, it is possible to use aprotic, nonpolar solvents such as pentane, hexane, heptane, octane, benzene or toluene as solvents.
It has been found that preferred active systems are obtained when the cocatalyst/catalyst ratio is in the range from 1:1 to 80:1, more preferably from 5:1 to 20:1.
It has been found that the cocatalyst/catalyst ratio can be reduced in the novel catalyst systems without decreases in activity resulting. In addition, the use of the novel cocatalysts in the polymerization of ethylene and propylene leads to an increase in activity in comparison with conventional catalyst systems. In this way, the catalyst systems of the invention can be prepared considerably more cheaply than corresponding, previously known systems. The cocatalyst/catalyst ratio can be reduced to values of from 20:1 to 1:1 without the yields and the desired product quality being influenced to a significant extent. Up to a ratio of about 2:1, no decreases in activity have to be accepted. Even above a ratio of 1:1, high activities far above those of conventional systems are achieved.
The catalyst concentration is preferably in the range from 10xe2x88x922 to 10xe2x88x926 mol/l, more preferably from 10xe2x88x923 to 10xe2x88x925 mol/l.
The catalyst or cocatalyst loading on MgCl2 is preferably in the range from 0.5 to 5 mmol/g, more preferably from 1 to 3 mmol/g.
Owing to their lower sensitivity to moisture and air and their lower sensitivity to impurities when used in a polymerization, the novel catalyst systems can be handled more safely and give more reproducible results and also a greater, long-term stability in comparison with systems of the prior art.
The entire disclosure of all applications, patents and publications, cited above, and of corresponding German application No. 10010796.6, filed Mar. 8, 2000 is hereby incorporated by reference.